First look: Delta 7 Ascend road bike

IsoTruss open lattice carbon frame from Utah

Delta 7 is a Utah based company, and one of a handful of bicycle brands showing at the inaugural Press Camp in Sun Valley, Idaho this week.

Delta 7 Sports came on the scene in 2007 with its IsoTruss carbon open lattice tube design, starting with the US$4,895 Arantix mountain hardtail frame. In Idaho, we checked out the new US$5,995 Ascend road bike frame.

With only a few hundred frames produced, the premium-priced Delta 7 line has certainly turned some heads.

The funky frame is made of carbon fibre and Kevlar IsoTruss tubes with carbon fibre lugs, with minimal aluminium where components attach.

According to marketing vice president Lester Muranaka, while the Ascend frame isn't lighter than competing carbon frames, its open lattice construction actually provides superior resilience and damage tolerance characteristics. In short, the IsoTruss is able to isolate impact and prevent damage from spreading beyond the next intersection. Additionally, the redundant structure will balance and carry loads even if a member is damaged.

At first glance, it's easy to be skeptical of the tubing's structural integrity. Muranaka assured us the Ascend frame bends less, twists less (torsion) and flexes less (axial stiffness) than solid surface bike frames of the same weight.

Asked if the frame collects more dirt and is harder to clean than a standard solid tube surface, Muranaka said the contrary is true. A simple frame rinse with a hose will clean things quickly, without any worry of corrosion. Each junction is capped to keep moisture out of the lugs.

According to Muranaka, wind-tunnel results show a net reduction in aerodynamic drag over frames made with a solid surface. Air passes directly through the tube to eliminate what Muranaka calls a vortex behind the tube, outweighing the amount of turbulence caused by "sifting" the air through the open lattice IsoTruss.

While the initial prototype took nearly 300 hours to produce, Muranaka told BikeRadar production has come down significantly at the Payson, Utah facility.

The patented IsoTruss was developed at Brigham Young University under the direction of Civil Engineering professor David W. Jensen at the Center for Advanced Structural Composites.

A 56cm Ascend frame weighs 1,050g/2.3lbs. Delivery is four weeks, with a US$1,000 deposit. Sizes include 50, 54, 56, 58 and 60cm, and come with a lifetime warranty.

For more information, visit www.delta7sports.com.

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